This invention relates to cellular core structural panels and more particularly, to honeycomb type core panel with face sheets which are not laminated to the core by conventional means.
Honeycomb materials made of paper, metal or plastic are widely used as a core material in the manufacture of panels. Such panels find application for various industrial uses where high strength to weight ratios are desirable. They are widely used in the aerospace industry for air frame parts, as well as in the construction industry for doors, shelves, partitions, accoustical panels, etc. Also, they have found use in the transportation industry, as, for example, in busses and recreational vehicles. The lightweight feature of honeycomb core panels, essential in the aerospace industry for many years, has now become more attractive for other type transportation vehicles where it is increasingly desirable to reduce weight and hence fuel consumption.
To date, honeycomb core structural panels have been fabricated by laminating face sheets or "skins" to the cellular core, by adhesive bonding or brazing, as for example, in U.S. Pat. No. 3,257,253 "Laminated Cellular Panel" or U.S. Pat. No. 3,365,787 "Method of Making Metal Honeycomb Sandwich Structure". In U.S. Pat. No. 2,910,153 "Structural Panel of Honeycomb Type", a thin flange is provided on the upper and lower edge of each core strip. The flange is recessed in areas where it is to mate with an adjacent core strip, so the core strips may be resistance welded directly to one another.
Conventional laminating techniques require first fabricating the honeycomb core and then laminating separate face sheets by adhesively bonding, brazing or welding. On account of the separate sheet lamination, close thickness tolerances for the core must be maintained so the face sheets may be bonded to the core along its entire surface. Also, during bonding, care must be taken that pressure is applied to the face sheets directly normal to the core so no sideway slippage occurs. The panel is usually trimmed to size and formed after the laminating steps.
It is an object of this invention to provide a method of manufacturing a cellular core structural panel in one continuous process.
It is a further object of this invention to eliminate the need of laminating separate skins to core material in manufacturing a cellular core panel and to provide a process in which the skin is integral with the core.
It is another object of this invention to provide a method of manufacturing a completed cellular core panel from a coil of continuous sheet material.
It is another object of this invention to provide a process to manufacture panels of varying sizes without the need for cutting or carving separate core material.